Fifteen years after a person quits smoking, the risk for heart disease is that of a nonsmoker. But you do not have to wait 15 years to see the effects of quitting: Right after you stop smoking, your risk of death from heart disease lowers by one-third. “Your blood pressure lowers right away, and your risk of mouth, throat, esophageal and bladder cancer is reduced by half, just five years after you quit,” says Keser.